IS 1'OLYPODIACEAE (FERN FAMILY) 



2. POLYPODIACEAE R. Br. FERN FAMILY 



the leaves (fronds) often much branched, circinate in verna- 

 ~ing from a root stock. Spores of one kind, borne on the under surface 

 or margins of the leaves in sporangia (with an elastic ring), which are de- 

 veloped from a .-ingle epidermal cell. Prothallia above ground, green. The 

 .vporan.iria arc usually collected in little masses (fruit dots or sori), which are 

 often covered by a scale (indusium), which is produced by a cellular ougrowth 

 from the frond, or by a general involucre formed from the infolded margin of 

 tin- frond. Eaton, Ferns of North America. 



Leaves of tw<> kin. Is; the sterile broader than the fertile . . . 1. Cryptogramma. 

 Leaves all alike. 



Indusium wholly wanting. 

 iorsal, roundish. 



Leaves 2-3-pinnatifid 2. Phegoptens. 



Leaves simply pinnate 3. Polypodmm. 



Sori marginal, elongated 4. Notholaena. 



Indusium present. 



Formed from the inflexed leaf-margin. 



Sporangia on the underside of the reflexed portion of the leaf . 5. Adiantum. 

 Sporangia in a continuous vein-like groove, or receptacle, 



which connects the ends of the veins. 

 Large plants of moist copses ...... 6. Pteridium. 



Small plants of cliffs and rock slides. 



Pinnae tomentose or scaly beneath ..... 7. Cheilanthes. 



Pinnae smooth beneath 8. Pellaea. 



Formed from epidermal cells (not from the leaf-margin) and 



variously attached. 

 Sori round. 



Indusium superior, reniform or peltate, attached by a 

 central stalk. 



Sori near the midvein of the leaf 9. Dryopteris. 



Sori near the margin of the leaf 10. Polystichum. 



Indusium inferior or partly so. 



Hood-like, attached to the inner side, soon open on the other 11. Filix. 

 Cup-like, attached underneath, bursting above into a 



fimbriated margin 12. Woodsia. 



Sori oblong or linear 13. Asplenium. 



1. CRYPTOGRAMMA R. Br. ROCK BRAKE 



Rootstocks short, bearing numerous light-green small smooth fronds of two 

 kinds; the sterile much broader than the taller fertile ones; all with stramineous 

 stipes. Sori extending down the free veins. Involucre very broad, at length 

 flattened out and exposing the now confluent sori. 



iftod; fronds 3-4-pinnate 1. C. acrostichoides. 



uttered; fronds 2-3-pinnate . . . . . . 2. C. Stelleri. 



1. Cryptogramma acrostichoides R. Br. App. Frank, Journ. 767. 1823. 

 Fronds ."> K) cm. long, chartaceous, ovate, closely 3-4-pinnate; pinules ovate 

 or ohovate, adnat e-decurrent, those of the fertile fronds narrower and longer, 

 the involucres very broad: sori extending far down the veinlets. In dense 

 patches among rocks; California to Colorado, thence far northward and east 



ike Superior. 



J. Cryptogramma Stelleri (Gm.) Prantl, Engler's Bot. Jahrb. 3: 413. 1882. 



lender, creeping, nearly naked: fronds very delicate, 5-10 cm. 



ite. pinnate with a few once or twice pinnatifid pinnae; seg- 



oblonn or obovafe; involucres broad and delicate. Pellaea gracilis. 



lamp mid shaded limestone rocks; Colorado, northward and east- 



uatd t<. Labrador, and thence south to Pennsylvania. 



2. PHEGOPTERIS Fee 



/.ed fenis with leaves L> -3-pinnate, triangular-ternate, the primary 

 ;i -talked :i nd the rachis not winged. Sori small, on the back of the 

 In-low their attenuate apices. Indusium wholly wanting. 



